MXPA99008939A - Tubing restoring bumpers for improved accuracy peristaltic pump - Google Patents

Abstract

An apparatus in a medical delivery device for biasing tubing having a select original cross section which is subject to compression and relaxation to substantially its original cross section upon relaxation. The apparatus includes a plurality of bumpers disposed lengthwise of the tubing operatively associated with the tubing to bias the tubing to its original cross section and spaced relative to adjacent bumpers to provide for free expansion of the tubing as it is subject to compression.

Description

PIPE RESTORATION TOPES TO IMPROVE THE PRECISION OF THE PERISTAL PUMP FIELD OF THE INVENTION This invention is directed directly to liquid delivery devices for controlling the flow of liquid from a reservoir of liquid, and very particularly toward the reservoir stops for improving the accuracy of the peristaltic pump.

BACKGROUND OF THE INVENTION Peristaltic pumps are particularly recommended for use in accurate and injected measurement of fluids such as drugs within the bodies of hospital patients. American Patent Hemin to No. 4,893,991, discloses a linear type of peristaltic pump, American Patent No. 5,055.01, discloses a type of valve / plunger of the peristaltic pump. US Pat. No. 3,999.91 discloses a rotary type of peristaltic pump. Each of these peristaltic pumps functions to propel liquid through a REF: 31246 flexible pipe which is typically made of a flexible plastic material such as polyvinyl chloride or the like. The pipe is repeatedly compressed and expanded sequentially along a defined section of pipe. The pipe is typically expanded or 'bounced' by its internal elasticity.A known problem with this type of pump is that the part of the pipe which is intermittently compressed and expanded tends to fatigue over time.As a result, the pipeline is less willing to return to its original cross-section when it is released, decreasing the volume of the pipe along an expanded critical segment and thereby degrading the accuracy of the pump.American Patent No. 4,893,991 distinguishes that such pumps have been found to provide as much as 10% drip in the flow range over a period of 24 hours The previous branch has recognized this short display in peristaltic pumps and has tried at least three means to solve the problem. , Heminway American Patent No. 4,893,991, attempts to improve the accuracy of the pump by preventing the part of flexible tubing which is subject to compression. expansion and expansion from the cylindrical configuration assumed after the expansion. That is, the pistons which compress and expand the tubing are designed to keep the tubing segment in an oval cross section even at full expansion. A major problem with the solution given below in Heminway is that it requires very accurate tolerances with the pistons in the retracted position and that the pipeline be expanded to a consistent oval cross section so that the pump operates in precise ranges and volumes. In addition, because the pipe is not willing to assume its full circular cross-section, and therefore its larger volume, Heminway in turn restricts the range of liquid that can be pumped.

Natwick American Patent No. 5,055,001 proposes an even more complicated solution to improve the accuracy of peristaltic pumps. Natwick proposes that the range of diametral compression of the pipe be approximately 15% with the plunger retracted to about 85% with the plunger extended. Natwick argues that since the pipe never needs to recover to a completely decompressed condition, it changes in the elasticity of the flexible pipe due to continuous use and the repeated compression has much less effect on the volumetric capacity of the pump. In addition, because the plunger never fully compresses the expanded part of the pipe, the pipe is subject to less fatigue. Natwick also provides a mechanical pipe modeler arranged on each side of the plunger which is extended to reform the expanded part of the pipe as soon as the plunger is retracted and the pipe filled with fluid. Natwick suffers from the same Heminway fault in which he restricts the volume of the pipe used for pumping and therefore limits the pump's output ranges. In addition, pipe modelers are complex mechanical structures which create an additional avenue for the potential failure of the pump. Furthermore, the mechanical modeler showed in Natwick that it requires a number of potentially expensive parts and complicates the assembly of the pump. The American Mannes patent, No. 4,585,442, discloses a controller of intravenous infusion range which operates on a flexible pipe which is supported between a pair of elastic bands. The elastic bands act on opposite sides of the outer diameter of the pipe in a compressed state to avoid restoring the pipe to its original cross-section after expansion. In this way the elastic bands inhibit the tendency of the tube to 'flatten' and return to only an oval cross section which degrades the accuracy of the range of the controller Unfortunately, the elastic bands act only on two discrete points to the detriment of the restoration of Moreover, the space between the elastic bands must be maintained at precise tolerances chosen to prevent the elastic bands compressing the pipe in an oval cross section if the bands are too closed or failing to restore the pipe to In addition, the Mannes structure requires that the elastic bands be displaced by an amount equal to the full displacement of the compressed piping.As a result, considerable energy must be used to compress the piping against the restorative force of the elastic bands. and invention is directed toward the solution of one or more of the problems discussed above.

BRIEF DESCRIPTION OF THE INVENTION A first aspect of the present invention is an apparatus in a medical liquid feeder device for bending a pipe having a selected cross section which is originally subject to compression and loosening to physically return to its cross section original after loosening. The apparatus includes a number of stops disposed longitudinally to the pipe and operatively associated with the pipe to bend the pipe to its original cross section, the stops being disposed in relation to the longitudinal adjacent stops to provide free expansion of the pipe which is subject to compression. The free expansion of the pipe is preferably provided by the longitudinal space of the adjacent stops to define an expansion space of the pipe between them. Most stops are also preferably arranged with stops on opposite sides of the pipe. The stops on opposite sides of the pipe are spaced apart from each other a distance substantially equal to an outside diameter equivalent to the original cross section of the pipe. The compression of the pipe can be provided by a plunger acting on a selected longitudinal segment of the pipe, the plunger having a compression surface corresponding to the longitudinal segment of the pipe. The expansion space of the pipe is adjacent to the longitudinal segment of the pipe. The stops are preferably made of an elastomer. Another aspect of the invention is a peristaltic pump for sending liquid from a reservoir of liquid to a selected location. The peristaltic pump includes a flexible pipe that has a wall defining a flow clear, with the flow clear being in contact with the reserve liquid. A majority of stops are arranged longitudinally to a swollen segment of the pipe. Each pair of stops are disposed on an opposite side of the pipe as the stop and spaced at a distance substantially equal to an equivalent outside diameter of the pipe. Each adjacent stop is spaced a longitudinal distance from the swollen segment of the pipe to define an expansion space of the pipe. A plunger corresponds to each expansion space of the and is operatively associated with the swollen segment of the pipe. Each plunger is selectively extended and retracted relative to the longitudinal segment of the expanded segment between an extended and retracted position, with the plunger in the extended position collapsing the flow gap into a collapsed state and the plunger in the retracted position allowing the pipe wall to be restored to a non-collapsed state. An operator sequentially moves the pistons between the extended and retracted positions and thus moves the liquid through the flow clear from the reserve to the selected location. Preferably, the stops are made of an elastomer. The peristaltic pump may further include a channel defined between the opposite walls of a support block measured to receive the expanded segment of the pipe. The stops are arranged between the opposite walls of the support block and the wall of the flexible pipe. The support block and the stops are preferably integrally made of a single piece of an elastomer. Another aspect of the present invention is a liquid releasing device for controlling the flow of liquid from the liquid reservoir. The liquid releasing device includes a flexible pipe having a wall defining a flow clear, the flow clear being in contact with the liquid with the reservoir. Two pairs of stops are arranged longitudinally to the control segment of the pipe. Each stop of each pair of stops is disposed on the opposite side of the pipe as the other stop and spaced a distance substantially equal to the equivalent of the outer diameter of the pipe. The pair of stops are spaced a longitudinal distance from the control segment of the pipe to define a pipe expansion space. A piston corresponding to the expansion space of the pipe is associated operatively with the control segment of the pipe. The plunger is selectively extended and retracted relative to the longitudinal segment of the pipeline control segment between an extended position and a retracted position, with the plunger in the extended position collapsing the flow gap into a collapsed state and the plunger in a position retracted allowing the flow clear to be restored to a non-collapsed state. In this way, the effective cross-sectional area of the flow clear is varied for different liquid flow capacities of the flow clear. Preferably, the liquid releasing device further includes a support block having a channel measured to receive the expanded segment of the pipe. The channel is defined between the opposite walls of the support block and the stops are disposed between the opposite walls of the support block and the flexible pipe. The support block and the stops are preferably integrally formed in a single piece of one piece. Most of the stops operatively disposed relative to the expanded segment of the pipe bending the expanded segment of the pipe to its cylindrical configuration. The expansion spaces corresponding to the pistons receive a part of the displaced wall of the pipe, avoiding the need to displace the stops by themselves. In this way the amount of energy required to collapse the tube is reduced by the amount of energy that would be required to compress the pipe where the distorted part of the pipe required to move the stops. The closed longitudinal space of the stops allows the stops to assist the full restoration of the pipe to its original unconstrained cross section configuration when the plunger is moved to a retracted position. Thus, improvement of the accuracy of the peristaltic pump is provided by the tendency of the pipe to return to its decompressed configuration when the plunger is in its retracted position, while a minimum amount of energy is required to compress the pipe when the Plunger is extended. The minimization of energy consumption can be of enormous significance, particularly where the peristaltic pump is used with ambulatory patients and is operated by batteries. The requirements in the decrease of energy can mean to extend the life of the batteries. further, because less energy is required to compress the pipe a small motor can be used, also decreasing the energy requirements and allowing the manufacture of peristaltic pumps of greater efficiency, smaller size and lighter.

Brief description of the figures Fig. 1 is a perspective view of an expander mechanism of a peristaltic pump according to the present invention with a portion of the plate and the pump operator removed for clarity; Fig. 2 is a sectional elevated view, taken along line 2-2 of fig. 1; fig. 3 is a sectional view taken along line 3-3 of FIG. 2; and fig. 4 is an alternative embodiment of the invention of the same perspective as fig. 3.

Detailed description of the chosen modality The expander mechanism 10 of an exact improved peristaltic pump is shown in a perspective view in fig. 1. The expander mechanism includes a cylindrical flexible pipe 12. The cylindrical pipe 12 is made of a flexible plastic material such as polyvinyl chloride and which is well known in the art. A support block 14 has a channel 16 formed within the opposite opposed walls 18. A number of stops 20 extended longitudinally to the channel of the opposite walls 18. The stops 20 are arranged in pairs of stops 22 extending from one to the other of the two. opposing walls 18. Each stop 20 of each pair of stops 22 is spaced from the other a distance substantially equal to the outer diameter of the cylindrical pipe 12, which is received between them. The pairs of stops 22 are spaced apart longitudinally along the channel 16 to define the expansion spaces 24 to release the expansion of the pipe when the pipe is subject to compression. The bridges 26 extend between the pair of stops 22. Between the adjacent bridges a path 28 is defined. As best seen in FIG. 3, the path 28 receives a plunger 32. In the embodiment illustrated in FIG. 1, the support block 14, the stops 20 and the bridges 26 are integrally formed of a single block of an elastomer. Alternatively, the stops 20 can be made of an elastomer while the support 14 is made of a rigid material such as a metal or a rigid thermoplastic. In addition, the bridge 26 can be eliminated without affecting the stops of executing its functions as will be discussed below. The expander mechanism 10 further includes a case 34 including a recess 36 configured to receive the support block 14. The case 34 is preferably made of a rigid material to enclose the support block 14. A plate 38 fits through the mouth of the housing. channel 16 to provide a surface against which the pipe 12 is collapsed by the pistons 32, as illustrated and described below with respect to FIG. 2. Even though the plate is not illustrated, preferably part of a door which can be opened by a pivot to allow access to the channel to load the tube 12 into the channel.

The expander mechanism 10 further includes an operator of the pump 42, shown in FIG. 2. The pump operator 42 comprises a number of beds 44 eccentrically connected to an operator post 46. The operator post 46 is rotated operatively associated with the motor operator, which is not shown. The plungers 32 have a first end 47 associated ope ratively with an expanded segment 48 of the pipe defining a compression surface and a second end 49 associated with a bed 44. As is well known in the art, the operator of the The pump 42 is configured to sequentially extend and retract the plungers 32 relative to the longitudinal segment of the expanded segment of the tube between an extended position and a retracted position. With the plunger in the extended position, the flow clearance 52 of the tube 12 is collapsed to a collapsed state 53 and with the plunger in the retracted position a flow clear is restored to a non-collapsed state 54.

Fig. 3 illustrates the function of the stops 20. With the plunger 32 in the extended position, a longitudinal segment of the expanded portion of the wall of the pipe 55 is expanded or deformed and pushed into the expansion space 24 between the adjacent stops 20. When this occurs the corners 56 of the stops 20 are compressed as illustrated in FIG. 3, which is an adjoining part of the support block 14. When the plunger returns to its retracted position the bumpers of the compressed struts and the adjacent part of the support block 41 work along with the flexible wall of the pipe to restore the pipe to its original configuration, as seen at 58. A main advantage of the expansion space 24 is that the deformed portion of the wall of the pipe 55 fills this expansion space without having the deformation of the corresponding section of the stop 20. In this way, the energy required to compress the wall of the tube 55 is minimized. However, the stops are close enough to provide substantial assistance in restoring the pipe to its original cross section. As illustrated in fig. 3 the compression surface of the plunger 32 preferably substantially fills the cross section of the expansion space 24. FIG. 4 illustrates an alternative embodiment of the invention. In this embodiment the stops 20 'and the support block 14' are made of a rigid material. In order to provide an adequate volume for the deformed pipe 54, the expansion spaces 24 'are as wide as the plunger 32'. Still, the relative closeness of the stops 20 'helps the restoration of the pipe to its original cross-section when the plunger 32' returns to its retracted position. The improved expander mechanism of the peristaltic pump of the present invention provides assistance to the flexible tubing in that restored by it to its original cross section following the compression of a plunger, while minimizing the energy required by the plunger to collapse the flow clear . By minimizing the amount of energy needed to collapse the pipe, the small power source can be used and a small, lightweight motor can be used to operate the pump. Furthermore, a small, lightweight operating mechanism can be used, all contributing to more efficiency of small, lightweight peristaltic pumps.

DECLARATION OF THE BEST METHOD KNOWN TO CARRY OUT THE INVENTION It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following

Claims (1)

1. CLAIMS An apparatus in a medical liquid feeding device for bending a pipe having an original cross section selected with a pipe segment which is subject to compression and loosening to substantially return to its original cross-section after loosening, the apparatus characterized because it contains: a plurality of stoppers and longitudinally arranged co-ordinates longitudinally attached to the associated pipeline with the pipe to return the segment of the pipe to its original cross-section, the stops being arranged in relation to the pipes. longitudinal adjacent stops to provide free expansion of the pipe segment when it is subject to compression. The apparatus of claim 1 characterized in that the free expansion of the segment of the pipe is provided by the longitudinal spacing of the adjacent stops to define an expansion space between them. The rei indication apparatus 1 characterized in that most of the stops are furthermore disposed with the stops on the opposite sides of the pipe spaced apart from each other a distance substantially equal to an outer diameter equivalent to the original cross section of the pipe. The apparatus of claim 1 characterized in that the stops are arranged in pairs of stops along the pipe, each stop or each pair of stops are arranged on an opposite side of the pipe and spaced a distance substantially equal to an equivalent outside diameter of the original cross section of the pipe. The apparatus of claim 4 characterized in that the free expansion of the pipe segment is provided by the longitudinal spacing of the adjacent stops to define an expansion space of the pipe between them. The apparatus of claim 2 characterized in that the pipe segment is subject to compression by a plunger having a compression surface corresponding to the segment of the pipe, the expansion space of the pipe being adjacent to the pipe segment. The apparatus of claim 6 characterized in that the compression surface of the plunger physically fills a cross section of the expansion space of the pipe. The apparatus of claim 1 characterized in that it also comprises a support block having a channel therein arranged to receive the pipe longitudinally, the channel being defined between the walls of the support block and the stops being disposed between the opposite walls of the block. support and the pipe. The apparatus of claim 9 characterized in that the stops and the support block are integrally made of a single piece of an elastomer. A peristaltic pump for supplying liquid from a reservoir of liquid to a selected location, the peristaltic pump characterized in that it contains: a flexible pipe having a wall defining a flow clear, with the flow clear in contact with the reserve liquid; a plurality of plungers each associated operatively with a longitudinal space of an expanded segment of the pipe, each piston being selectively extended and retracted in relation to a longitudinal segment of the pipe of the expanded segment between an extended position and a position retracted, with the plunger with the extended position collapsing the flow gap of the longitudinal segment of pipe to a collapsed state and the plunger in the retracted position allowing the flow clear of the longitudinal segment of the pipe to be restored to a non-collapsed state; a number of pairs of stops of the longitudinally disposed ends of the expanded segment of the pipe, each stop of each pair of stops being disposed on an opposite side of the pipe as the other stop and spaced a distance substantially equal to one equivalent of outer diameter of the tube, each pair of adjacent stops being spaced a longitudinal distance from the expanded segment of the pipe to define a different expansion space of the pipe between them corresponding to each piston; and a sequential operator moving the pistons between the extended and retracted positions and as to move the liquid through the flow clear from the reservoir to the selected location. The peristaltic pump of the claim - | or characterized in that the stops are made of an elastomer. The peristaltic pump of the claim 1 C a c eri zed because the plunger is configured to physically fill the expansion space. The peristaltic pump of the claim 10 characterized in that it also contains a support block having a channel therein arranged to receive the expanded segment of the pipe, the channel being defined between the opposite walls of the support block, the stops being disposed between the opposite walls of the support block. and the wall of the pipe f1 ex ib 1 e. The peristaltic pump of claim 13 characterized in that the support block is made of an elastomer. The peristaltic pump of the claim 13 characterized in that the support block and the stops are integrally made of a single part of a turner. The peristaltic pump of the claim 15 characterized in that it also contains a bridge formed integrally with the stops and the support block extending each stop of each pair of stops with adjacent bridges defining between them a trajectory for the plunger within the channel. a liquid releasing device for controlling the flow of liquid from a liquid reservoir, the liquid releasing device characterized in that it contains: a flexible pipe having a wall defining a flow clear, the flow clear being in contact with the liquid of the reserve; two pairs of stops 1 and 1 or more arranged longitudinally to a control segment of the pipe, each stop of each pair of stops being arranged on an opposite side of the pipe as the other stop and spaced a distance substantially equal to one equivalent outer diameter of the tube, the pair of stops being spaced a longitudinal distance from the control segment of the pipe to define between them a space for expansion of the pipe; a piston corresponding to the expansion space of the pipe is operationally associated with the segment of the control of the pipe, the piston being selectively extended and retracted relative to the longitudinal segment of the control segment between an extended position and a retracted position, with the plunger in the extended position by collapsing the flow clear to a non-collapsed state and the plunger in the retracted position allowing the flow clear to be restored to a non-collapsed state, whereby the effective cross-sectional area of the clearing flow can be modified to vary the capacity of the flow clear. A peristaltic pump for sending liquid from a reservoir of liquid to a selected location, the peristaltic pump characterized in that it contains: a cylindrical flexible tubing having a wall defining a flow clear, with the flow clear in contact with the liquid the reserve; a support block having a channel within which it receives an expanded segment of the pipe, with the channel being defined between the opposite walls of the support block, the support block also contains a number of buffer pairs the as-omer s extending within the channel from the opposite walls and longitudinally disposed to the expanded segment of the pipe, each stop of each pair of stops being disposed on an opposite side of the pipe as the other stop and spaced a distance substantially equal to the outer diameter of the pipe. pipe to return the pipe to its cylindrical configuration, each adjacent pair of stops being spaced a longitudinal distance from the expanded segment of the pipe to define between these a pipe expansion space; a plunger corresponding to each expansion space of the pipe operatively associated with the expanded segment of the pipe, each plunger being selectively extended and retracted relative to the longitudinal segment of the expanded segment between an extended position and a retracted position, with the plunger at the extended position collapsing the flow clear to a collapsed state and the plunger in the retracted position allowing the wall of the pipe and adjacent stops to restore the flow clear to a non-collapsed state; and an operator sequentially moving the pistons between the extended and retracted positions and as to move the liquid through the flow clear from the reservoir to the selected location. The peristaltic pump of the claim, characterized in that the stops are made of an elastomer. The peristaltic pump of the claim 18 characterized in that the plunger is configured to physically fill the expansion space. The peristaltic pump of the rei indication 18 characterized in that the support block and the stops are integrally formed of a single part of a turner. The peristaltic pump of claim 18 characterized in that it also contains an integral bridge formed with the stops and the support block extended between each stop of each pair of stops, with the adjacent bridges defining between these a path for the plunger within the channel.